autopano-sift-C can be used to find control points in overlapping image pairs and is a C port of the C# software autopano-sift. It is somewhat faster and doesn't require a C# runtime - Installing the mono C# runtime on OS X has proved to be problematic on some systems.

autopano-sift-C is available from the hugin project and can only be used within hugin as an optional installation due to patent issues: the use of the Scale-invariant feature transform algorithm is restricted by US Patent 6,711,293, awarded March 23, 2004 to the University of British Columbia.

The current version 2.5.1 (autopano-sift-C-2.5.1) is available since the release of hugin 0.7 in October 2008.